Monday, July 31, 2017

But Wait! THIS Summer isn't even over yet! Explore the Colorado Plateau, June 2-17, 2018 (Put it on your calendar now!)

North Rim of Grand Canyon National Park (yes, Gaelyn, we'll be on the North Rim, hope to see you there!)
"Wait!", you are saying, "it's still the summer of 2017! Why are you talking about the summer of 2018?" It's a fair question, and the answer is predicated on an unfortunate truth: our parks are too small and too crowded. If I hope to mount a field studies expedition NEXT summer, I have to start making the reservations right now. That's what I was up to today, and it occurred to me that it's never too early to put something on your calendar. We'd love to have you join us next year, on June 2-17, 2018.

There is no place on this planet like the Colorado Plateau. It's hard to find anyplace else on Earth where the crust remained relatively stable for upwards of a billion years, accumulating several miles of horizontal sediments, only to be lifted up rapidly in the last few million. The Colorado River and her tributaries then stripped away much of the sedimentary cover, and cut deep into the underlying metamorphic rocks, which record a violent geologic history of colliding landmasses and mountain-building. The resulting landscape is one of the most beautiful places imaginable.
Angels Landing Trail in Zion National Park, Utah
The plateau country is a training ground for geologists and earth scientists, and has been since the days of John Wesley Powell and Joseph Ives, who were the first to lead research parties into the region (they didn't "discover" the plateau, of course; Native Americans have known the region for thousands of years). If you are curious about learning geology in this incredible region, you might consider joining us as a student (of any age) on our geology field studies course Geology 191, offered under the auspices of Modesto Junior College in Modesto, California. The course is designed to fulfil the curiosity of lay geologists and archaeologists, but also to build the skills of geology and anthropology majors as well.
Goosenecks of the San Juan River, Utah
Our field course will be a grand loop through the plateau country, with investigations of the Mojave National Scenic Preserve, Grand Canyon, Zion, Bryce, Arches, Canyonlands, Capitol Reef, Black Canyon of the Gunnison, Mesa Verde and Great Basin National Parks, as well as many monuments, including the new Bear's Ears, Grand Staircase-Escalante, Natural Bridges, Navajo, Hovenweep, Colorado, and state parks like Goblin Valley and Berlin-Ichthyosaur. It will be an unforgettable two week trip from June 2-17, 2018, beginning and ending in Modesto, California. Information can be found soon at my school website at
Black Canyon of the Gunnison National Park in Colorado
It's not a comfortable trip...we travel in school vans (which of course are known for their luxuriousness!), we camp every night, and the days can be hot, windy, cold, stormy, and we are out in the middle of anything that happens. But we are staying in beautiful places each night, and there are even showers and laundry available every third day or so! Extensive hiking is not required, but there will be many chances to explore the parks and monuments that we are visiting.
Double Arch in Arches National Park in Utah
Geology 191 is a 3 semester unit course which will be taught as a dyad with Anthropology 191 (also 3 units). By end of the course, you will be able to see the landscape the way geologists do: by identifying rocks, minerals and fossils, and interpreting the geological history of an area by working out the sequence of events as exposed in outcrops. If you are a science teacher, you will come home with a collection of photographs that illustrate most of the important principles of geology, and a selection of rocks, minerals and fossils that will make a great classroom teaching tool (legally collected, of course; there are many localities outside of protected parks from which to collect samples). The dual nature of the course means that you will also have a mastery of the archaeology of the plateau region, the home of the Ancestral Puebloans, the Fremont people, the Navajo, the Utes, and others.
Canyonlands National Park, Utah
The cost of the trip will be about $850.00 plus the cost of tuition (Currently $46 per unit for California residents, and $222 per unit for out-of-state residents). The cost includes transportation, food, camp fees, and entrance fees. Participants would want to bring a few dollars along for showers, laundry, and souvenirs.  The food is tasty and plentiful (everyone helps cook and clean!), and the school vans...are vans.

For those of you who live in the Modesto region, we are having an organizational meeting in April, towards the end of the spring semester.

If you are not in the area, we will be glad to arrange for transportation from nearby airports and train stations (we actually have an Amtrak station in town). Enrollment can be completed online once you are registered with the college ( Please contact me through the class website if you have any questions.
Bryce Canyon National Park
Hope to see you out there, back of beyond!

Saturday, July 29, 2017

Walking on Broken Glass, Literally: And what is slabby pahoehoe?

Some places on our planet are just not like anywhere else.

Kilauea, on the Big Island of Hawai'i is one of the most volcanically active places on Earth, and very few parts of its surface are older than a thousand years, and most are much younger. It's a place where erosion is essentially a non-existent process. There is only the addition of rock during eruptions, or the collapse of rock (into caldera or pit craters).

Walking on a landscape that has existed for only a few years is truly an otherworldly experience. A raw surface, unsoftened by soil formation or plant cover, is not a normal experience for most human beings. I was at Kilauea in May for a conference and field trip, and we had a chance to walk across one of Kilauea's more recent extrusions, a lava flow near Halemaumau Crater in the caldera that erupted in 1982. The eruption destroyed several hundred feet of the highway that travels around the caldera. It was quickly repaired, but has been closed more recently because of the ongoing (since 2009) eruption in the depths of Halemaumau that is putting out deadly fumes and gases, and the occasional explosion of debris. We were allowed to enter the area on this particular day.

Even if you have walked on basalt flows on the U.S. mainland, the experience is not like this one was. I've always thought of lava flows as being firm and solid, but when they are new, that is not always the case. The entire flow seemed to be covered by loose flakes about the size of potato chips.

One could never sneak up on an adversary on a surface like this. Every step produced loud crunching sounds. A close inspection of the loose chips showed why. The chips were composed not of basalt, but of glassy obsidian!

The more familiar kinds of obsidian most often seen around volcanoes is richer in silica, and is usually associated with lava domes or plug domes, a type of volcano not found in Hawai'i. But all lavas can form glass when they cool rapidly, and that is what happened at the surface of this flow. As the lava was exposed to the cooler air, it quickly solidified, forming a glassy crust. One would think that would be the end of it, and that the whole flow would solidify almost as quickly. But it doesn't. Six weeks after the eruption ended, bulldozers were realigning the highway, and overturned slabs still glowed red.

Such flows continue to be mobile after the crust forms, and lava beneath the crust is still quite molten (it is insulated by the crust). The flow can actually inflate with molten lava, becoming a great deal thicker before a breakout occurs, and the lava drains away. The surface can rise and fall, breaking here and there into large slabs. At the same time, the cooling rock at the surface contracts, and the surface breaks up into the chips we were walking on. In videos of such flows, one can often make out the tinkling sound of the rocks snapping off.

The amount of deflation in this particular flow was considerable, as can be seen in the photograph above, exceeding seven meters or so (about 20 feet). The lava reminded me of a sheet on an unmade bed, partly pulled up over a pillow.

The cliffs were unusual for a Hawaiian-type volcano. They were made up of distinct layers that looked almost sedimentary. They didn't result from any sedimentary process, however. They record a series of violent ash eruptions that culminated in a very explosive event in 1790 that killed dozens, maybe hundreds of Hawaiian warriors, and changed the course of history on the island (the army was facing off against King Kamehameha, and the tragedy was seen as a sign from the gods). Kamehameha soon thereafter united all the islands under his rule.

We climbed the cliff for a perspective of the main part of the flow and steaming cauldron of Halemaumau in the near distance. Halemaumau is the abode of the volcano goddess Pele, and many people take her existence seriously, providing offerings and prayers.

I was fascinated by the swirls that became visible from our vantage point a hundred feet or so above the lava flow. It is much smoother than the lavas I experienced on previous trips along the southeast rift zone of Kilauea. Compare it, for instance, with the pahoehoe flows near the former village of Kalapana that I visited in 2004, only days after they were extruded. They have a more "ropy" lobe-like shape, but note the silvery color. That silver color is also a thin layer of glass. After a few decades or centuries, that silvery luster will weather away, and the flow will have the forbidding black color that most people associate with basalt lava.

Wednesday, July 26, 2017

What the Heck is a Superelevated Lava Flow Anyway? 1974 Basalt Flow near Keanakāko‘i Crater

Talk about catnip for a geologist... "Do Not Enter", "Stop Here", "Go no closer to the eruption", and "Roads and Trails Closed Beyond This Point". How could any self-respecting geologist ignore such signage? And yes, that is a volcanic plume emanating from a crater on the far right side of the picture. We headed right on by the signs and headed down the road...

I suppose I should mention that we were there legally as guests of the park service, on an officially sanctioned field trip. I know that takes a bit of fun out of the story, but I suppose it's better than documenting an adventure in trespassing. We were exploring the evidence for explosive eruptive activity at the Kilauea caldera in Hawai'i Volcanoes National Park, and were walking along the edge of Keanakāko‘i Crater.

Keanakāko‘i Crater ("cave of the adzes"), probably formed in the 1400s and for centuries it was an important source of a particularly hard form of basalt that could be used to make adzes, the tools used to carve canoes and logs for walls. The adze quarry was covered by a lava flow in 1877, and a later flow in 1974 buried the quarry even deeper. It was the 1974 lava flow that we were having a look at.

The flow emanated from a rift opening just up the slope and traveled down a gully towards the main part of the Kilauea caldera. It coated the gully walls with a thin layer of pahoehoe (smooth-surfaced) basalt as it drained into the deeper crater. In other words, it was less of a lava flow than a covering layer on the gully walls. This odd occurrence revealed something interesting.
Downflow, the lava appeared to be thicker, but as we walked lower, it was apparent that it was only thick on one side. What did that mean? It meant that we were looking at a superelevated flow. And no, I'd never heard of the term either.
This was a fast-moving flow, and as it moved down the gully it made a tight turn. With an estimated velocity of 30 kilometers per hour (19 mph), the flow climbed high up the slope as it banked to the right. That's how one bank ended up around 10 meters higher than the other. It was superelevated...

The flow must have been quite a sight as it careened down the canyon but I strongly doubt there were any witnesses, as it would have been incredibly dangerous and the radiant heat would have been deadly. Then again, someone would have put up warning signs, and any geologists would have found the signs irresistible. Maybe someone saw it after all!

Saturday, July 22, 2017

How Foolish Can These People Be? The Treasure of our National Monuments

Let's make something very clear: these lands belong to the American people. They have always belonged to the American people, dating back to the time of statehood. There were attempts at times to give some of the lands away a century ago under the Homestead Act, but no one wanted them (not that anyone was asking Native Americans at the time).
There are people who have borrowed these lands. Some of them were miners, others were oil drillers, some were ranchers. But they were renters, leasers, who owed fees to help keep the lands healthy. It may be that some of them feel they own these lands because they used them for decades, but if we go by that standard, the land belongs to the Native Americans who used these lands for thousands of years. But the ranchers and miners have persisted, and they finally seem to have found a "champion" in Washington. Secretary of the Interior Zinke and President Trump have suggested that they might rescind the national monument status of some of our most precious lands.
 The lands were set aside by proclamations of several presidents, both Republican and Democrat, under the auspices of the National Antiquities Act. Rescinding these monuments would be illegal, but there is no one in Washington apparently who will fight to protect them. Foremost among them are Grand Staircase-Escalante, and Bear's Ears, which are the monuments I am highlighting with these pictures.
The so-called "process" had to include public comments, and according to reports, the public support for these monuments has been on the order of 98%. But I fear that the desires of the American people will be ignored in Washington. This must not be allowed to happen.
There is local opposition to these monuments. Some of it has come, as noted above, from ranchers and miners. But I'm not going to mince words here: much of the local opposition is coming from pothunters who would despoil the heritage of the Native Americans who lived and died here for thousands of years. They fear monument status would mean more scrutiny and greater protection of the archaeological resources of these monuments. And it should. These people are criminals.
Those leading the local opposition, if they had a single brain among them, should be calling on Congress to make these monuments into national parks. I've been to Zion National Park and others in the region and they are so crowded that it is degrading the experience of visiting. It would be incredibly smart to capitalize on the demand for beautiful open spaces by making new parks to take on some of the tourism. These parks would be a marvelous addition to the crown jewels of our national heritage.
I'm making an economic argument for the protection of these lands, but the most important reason to preserve them is ethical and moral. These canyons and alcoves contain the heritage of numerous cultures, and we don't have the right to vandalize their history. We don't have the right to strip mine the sacred places of a people.
Do what you can to maintain the integrity of our national monuments. The time for comments is past, but you can make sure that your congressional and senate representatives hear from you. Please don't let these lands be stolen again. The destruction of the past is permanent, and the shame will be on us all if we allow it to happen.

Thursday, July 20, 2017

Wild Horses at Home on the Range in Eastern California

I've been on the road again, this time for a short trip through Nevada, Utah and Arizona. Wi-Fi has been rare, so I'm only just beginning to catch up with things. Our route took us into the wildlands east of the Sierra Nevada, and before we reached the border of Nevada near Benton Hot Springs, we were privileged with the sight of several small herds of wild horses.

Nearly all schoolchildren will remember that the wild horses of North America are not native to the continent, having been introduced by the Spaniards hundreds of years ago. What is less recognized is that horses are native to North America, it's just that they went extinct here at the end of the Ice Age. I've written about them before. What follows is a portion of one of my favorite posts from 2011:

The heritage of the horses is one of the greatest stories of evolution in North America. When the dinosaurs were removed from world ecosystems by events at the end the Cretaceous Period (65 million years ago), various kinds of smaller animals began to evolve to fill available environmental niches. Birds and mammals were highly competitive in terrestrial environments, and within several million years, many new species appeared in the geologic record. 52 million years ago, a small browsing animal called Hyracotherium fed on leaves in the forests. It was the size of a fox, with five toes per foot (though not all were used in locomotion). It was the earliest horse-like ancestor. Over the millenia, dozens of horse-related species evolved, with fewer toes and more highly developed hooves.

In the mid-Cenozoic, the forests were receding and vast grasslands began to develop. Some of the horses adapted to eating the grass, developing constantly growing teeth that could withstand the silica and dust without being worn away. They also grew larger and faster in order to deal with predators on the open plains. At times, a dozen or more different species of horses co-existed.

The horses were creatures of North America. Groups of them migrated into South America around 3-4 million years when the continents were joined at the isthmus of Panama. Another group migrated over the Bering Land Strait into Asia about the same time. But their home, the land of their ancestry, is North America. They thrived until around 12,000 years ago, when they and the 30 or so other species of the North American megafauna went extinct. The horses, camels, short-faced bears, giant beavers, sabertooth cats, American lions, dire wolves, and wooly mammoths all disappeared. The reasons are not known with certainty, but climate change related to the end of Pleistocene Ice Age is one possible culprit. Predation by newly arrived human beings is also suspected.

I grant that others have greater expertise than me on these matters, but the climate change idea seems problematic because there were many ice ages, more than a dozen, so why didn't these animals go extinct at an earlier time? ... Human predation makes the most sense to me, but further research will certainly be needed.

So, when Columbus and other Spanish explorers and invaders arrived in the New World with their horses in tow, they were bringing those horses back to their ancestral homeland. They did well in the wild, and over the centuries have been naturalized into the arid landscape of the Basin and Range province. Their existence is controversial, since they compete with cows and sheep for forage, and until federal legislation brought some level of protection, they were hunted and killed by ranchers. Today, they are "managed" by the Bureau of Land Management and other federal agencies, for better or worse.

I guess I'm wading into a huge controversy over the management of the horses, but I find it disturbing that there are many who only appreciate horses when they are doing work for us. Wild horses living free on the open range are to them a nuisance, as are the coyotes, wolves, and other predators that happen to eat the occasional cow or sheep. The lands the horses inhabit belong for the most part to all of us, not just the ranchers who borrow these landscapes. What I also know is that there is something beautiful about seeing these animals in the wild. There are so few creatures of the North American megafauna left, so it is a gift to see these creatures running free.

Friday, July 14, 2017

California's (not) Biggest, (not) Most Recently Active, and (not) Most Dangerous Volcano

Photo by Mrs. Geotripper
Mt. Shasta is no doubt the most dominating volcano in all of California. It's huge, topping out at well above 14,000 feet, and is visible from over a hundred miles in a number of directions. It was the first main stop on our recent journey exploring the Pacific Northwest and Northern Rocky Mountains, and it really stood out as we essentially circled it on our way to Lava Beds National Monument.

It's big, it's active, and it's potentially destructive. So how bad could it be? Is Shasta the biggest, most recently active and most dangerous volcano in the state? California has a great many volcanic features, and even though some are not as familiar to many of us, they do actually present a hazard for a great many more people than you might suspect. That's not to say that Shasta is not dangerous, however.
Castle Crags in the Klamath Mountains of northern California (photo by Mrs. Geotripper)
As Interstate 5 winds northward into the Klamath Mountains north of Redding, Shasta occasionally peeks out between the trees (the top picture), but for a brief moment near Dunsmuir a totally different set of mountain spires appear off to the west. They are the Castle Crags, a granite stock (an intrusive body of granite exposed over an area of less than 40 square miles; batholiths are larger).

Castle Crags (seen below in a picture from a plane flight a few years back) were relevant to our explorations because they represent a volcano from inside out. About 160 million years ago, the land surface was five or six miles above, and molten magma was moving up through the crust. Some of the magma reached the surface to flow in volcanic eruptions, building up volcanoes maybe similar to Shasta and others of the Cascades. The rest of the molten rock cooled slowly for tens of thousands of years, forming the crystalline granitic rock exposed today at the Crags.

Moments later, we made the imaginary journey up through the crust and onto the flanks of the modern volcanic edifice of Mt. Shasta. We followed the Everitt Highway up the mountain to the about the 7,500 foot level to have a look around. Even though we were on the first day of a crippling heat wave in California, the air was cool, and the snowbanks made it clear that winter was not yet entirely over.
Bunny Flats was the end of the road for us on this particular day. The last two or three miles of pavement above were covered by snow. The road used to end at a ski area, but the resort was closed years ago, due to avalanche danger (as I understand it; there is a newer resort on the lower slopes of the volcano). Working and playing on the slopes of a volcano does have its hazards...

There are a lot of hazards around Shasta. Lava flows might seem to be one of them, but andesite lava tends to be sluggish and slow. Lava doesn't worry me so much. Ash eruptions are certainly a danger, due to their speed and mobility. Shasta has had such eruptions, but they haven't been the usual modus operandi over the years. But...lava or ash flowing onto thick snow: that's a problem. The melting snow and debris quickly turns into a mudflow that can travel for tens of miles at high rates of speed. The Indonesians called them lahars, and the name has stuck. Most of the lower flanks of Shasta are mantled with lahar deposits, and the towns of Weed and Shasta City are built on them. Mudflows have even happened when there have been no eruptions. Meltwater can build up under the glaciers that cover much of the mountain and burst out with no warning (Icelanders call these glacial bursts jökulhlaups). All in all, it's a pretty dangerous volcano.

And it's active. There have been a number of eruptions in the last 10,000 years, including those that built up Shastina and Black Butte. The entire upper part of Shasta, the Hotlum Cone, is less than 9,000 years old. The volcano may have erupted in 1786. So is it the most recently active volcano in California? Nope.
From our vantage point at Bunny Flat, we had an unobstructed view southeast towards Lassen Peak and Brokeoff Mountain. Lassen is the winner of the "most recently active" designation. The plug dome began making noise in 1914, and let loose in 1915 with a lava flow, a destructive lahar, and an ash eruption that interrupted train service out in Winnemucca, Nevada. The eruption produced a mushroom cloud five or six miles high. Geothermal activity continues today in what is now Lassen Volcanic National Park.
Lassen Peak (left) and Brokeoff Mountain (right) from Bunny Flat

So what about the biggest? Surely a mountain 14,000 feet tall is the biggest volcano in the state of California? Well, it's certainly the tallest, and it is the most voluminous stratovolcano in the Cascades, but it actually isn't the biggest volcano in the state. When we camped that evening, we were ensconced on the flank of a massive shield volcano called Medicine Lake Highland. With the gentle slopes composed of basalt lava flows, it hardly looks like a volcano at all, but when you compare the width of the volcano in the picture below (it takes up three quarters of the skyline), you realize it is really big. It consists of around 130 cubic miles of lava, compared to about 108 for Mt. Shasta (which is the snow-capped peak on the right).

So it's the most dangerous, right?

Well...that's a hard concept to quantify. There are lots of volcanoes in California, and some are closer to population centers than others, and some are more capable of chaos and violence than others. The Clear Lake Volcanic Field, north of the Bay Area, has been active as recently as 10,000 years ago, and the Geysers Geothermal Area nearby shows that magma is still present at a relatively shallow depth. Several thousand people live in the general vicinity.

The Lassen Volcanic Center is an obvious threat, given the activity in 1914-17. There are only a few small villages in the immediate vicinity of the volcano, but it is a major tourist destination in the summer season. Lahars could presumably reach the Sacramento Valley.

The aforementioned Medicine Lake Highland is certainly still active, with eruptions as recently as 950 years ago. Although basaltic shields aren't known for violent eruptions, the presence of rhyolite plug domes around the summit area show that such eruptions are not out of the question. Like the others, the region is lightly populated.

Volcanism is also a possibility in Southern California, perhaps to the surprise of some. Young cinder cones dot parts of the Mojave Desert (the Lavic Lake Volcanic Center), and the Coachella Valley (the Salton Buttes). Some of the small volcanic cones are younger than 2,000 years old.

The "elephant in the room" in terms of volcanic hazards of California has to be the Long Valley Caldera, and the nearby Inyo-Mono Craters. Every time there is a jiggle on a seismometer in Yellowstone National Park the internet lights up with predictions of death and destruction, but the conspiracy nuts pretty much totally ignore California's version of a death volcano. An eruption that took place 760,000 years ago produced 125 cubic miles of ash that covered most of the American West (the three Yellowstone eruptions ranged from 67 to 600 cubic miles). Yellowstone has not had a volcanic eruption in 70,000 years. The volcanoes in the Long Valley area of California have erupted as recently as 300 years ago. No one is talking about a repeat of the catastrophe of the 760,000 years ago, but smaller eruptions could certain cause havoc in this very popular tourist area. There was a huge brouhaha in the 1980s that had a lot of implications for how public officials respond to potential geological disasters. I wrote an extensive blog post about the event a couple of years ago; you can read it here (it's one of my favorites).
So Mt. Shasta isn't the biggest volcano in the state, isn't the most recently active, and may or may not be the most dangerous. But does that mean we can disregard the volcano? Hardly. It could cause all kinds of mayhem in the wrong circumstances. And there is one more hazard here that is unique.

The area north of Mt. Shasta is a landscape characterized by a strange hummocky surface composed of volcanic rock, but the hummocks don't look like cinder cones or other volcanic features. Geologists didn't know what to make of this weird topography. Until Mt. St. Helens exploded on May 18th, 1980, that is. One of the most astounding events of that eruption was the collapse of the entire flank of the mountain into a debris avalanche that traveled for twelve miles down the Toutle River. It turned out that an ancient iteration of Mt. Shasta had a similar fate around 300,000 years ago, with a debris avalanche that traveled 28 miles, almost to the present location of the town of Yreka.
The debris avalanche on the north flank of Mt. Shasta. Shasta Lake, a reservoir, is on the left within the debris field (photo by Geotripper)..
It is hard to imagine events on this scale, but the geological world is full of events that challenge our perception. That was one of our themes as we set out on our two week journey, and it was only our first day on the road.

Sunday, July 9, 2017

Red Fox on the Tuolumne River

After traveling several thousand miles through half a dozen national parks, you'd think I would be tired of watching for wild animals, but no, that never happens. It was a nice surprise this morning to see this Red Fox (Vulpes vulpes) on my more or less daily walk along the Tuolumne River. This is the first time I've had a chance to get more than just a couple of quickly snapped pictures.

I've seen them a few times before in the area (one of my pictures of a fox is on the interpretive sign at the beginning of the trail), but it's been many months since I've spotted any. I'm pretty sure they've seen me more than I've seen them. This one was working its way across the slope where the metal stairwell climbs to the parking lot at the west end of the Tuolumne Parkway Trail. It's probably getting used to humans, as the new trail has proven popular.

There are two subspecies of Red Fox (out of around 45 worldwide!) that are native to central and northern California. One, the Sierra Nevada Red Fox, is exceedingly rare and lives only in the high country north of Yosemite National Park (it was recently sighted in Yosemite for the first time in a century). Another, the Sacramento Valley Red Fox, lives in the Great Valley north of Sacramento. This individual is neither; it is probably a descendant of foxes brought to the valley in the 1860s for hunting and fur production. The Red Foxes have adapted well to urban and agricultural development in the Great Valley (I've seen them on my mid-valley college campus), and they contribute to the control of rodent pests, but they may also be a detriment to the survival of the endangered San Joaquin Kit Fox, which has lost a vast amount of habitat and has a population of just a few thousand.

I saw a native Gray Fox in this same area several years ago. I don't know if they are co-existing, or if one has replaced the other.